\documentclass[11pt]{standalone} % use standalone or subfile to be included in another tex file
\usepackage{tikz}
\usetikzlibrary{decorations.pathreplacing}


\begin{document}

\begin{tikzpicture}[y=1cm, x=1cm, font=\footnotesize]
	% axis
	\draw[thick, ->] (-1,0) -- (15,0) node[anchor=north] {Time};
	
	% time points: node (name) [position] {text}
	\draw (0,-3pt)  node (tm121) 	[below] {\tiny $t{-}121$} -- (0,3pt);
	\draw (1,-3pt)  node (tm120) 	[below,draw] {\tiny $t{-}120$} -- (1,3pt);
	\draw (2,-3pt)  node 			[below] {\tiny $t{-}119$} -- (2,3pt);
	\draw (6,-3pt)  node			[below] {\tiny $\dots$}   -- (6,3pt);
	\draw (10,-3pt) node           	[below] {\tiny $t{-}1$}   -- (10,3pt) node (tm1) {};
	\draw (11,-3pt) node (t_below) 	[below,draw] {\tiny $t$}       -- (11,3pt) node (t_upper) {};
	\draw (12,-3pt) node (tp1) 	   	[below] {\tiny $t{+}1$}   -- (12,3pt);
	
	% curly braces
	\draw[decorate, decoration={brace, amplitude=8pt, mirror}] (tm120.south) -- node [below=8pt] {Use a \textit{120-month} rolling window to estimate the topic-word distributions $\phi_k$} (t_below.south);
	\draw[decorate, decoration={brace, amplitude=5pt}] (tm1.north) -- node [above=5pt] {Use articles in month $t$ to compute topic weights $\theta_d$ in month $t$} (t_upper.north);
\end{tikzpicture}

\end{document}
